Temperature information deeply inside objects, especially deeply in vivo, is limited by physical principle of time and space, and information transportation, and this makes it impossible to facilitate non-contact temperature measurement within 1000° C. Temperature is direct evidence that characterizes immune response and life activities. Hyperthermia cancer therapy expects to control temperature at cancerization parts at 45° C.-47° C. during hyperthermia process. Normally 45° C.-47° C. is a critical temperature point that ensures safety of normal cells and causes cancer cells necrosis gradually. Remote detection of temperature field information of cancer cells between lungs and livers are critical for breakthrough of the hyperthermia therapy. However, internal organs, bones, vessels or skin are a natural barrier for the temperature information. In other fields, temperature distribution at outlets of aero engines directly affect lifetime of turbines, fast measurement methods are to greatly improve performance of engines without changing temperature distribution field of turbines. Therefore, a more popularly used method for measuring temperature at deep sites of objects becomes a key technique for promoting development of biomedical and industrial fields.
Technically, it is comparatively difficult to apply the existing temperature measurement technique to temperature measurement of deep sites of objects. The magnetic resonance temperature measurement technique brings twilight for temperature field measurement of human beings, and it is difficult to apply the magnetic resonance temperature measurement to vivo (such as hyperthermia cancer therapy) temperature measurement. However, too weak magnetic property of molecular directly or indirectly leads to technical difficulty of measurement. Temperature characteristic parameters of hydrogen molecular in vivo cannot be pre-obtained, and during test, measurement of temperature difference is implementing by measuring the same point for two times before and after heating, and at the same time, a test point is required to be highly static, which form a main source of error. Researchers notice that magnetic moments of magnetic nanoparticles (tri-iron tetroxide) are three orders of magnitude higher than nuclear magnetic signals of hydrogen molecules soon. Thus, the nano magnetic measurement system is expected to achieve high speed and high signal-noise ratio. J. B. Weaver from America made useful exploration of the nano magnetism, and he used the ratio between the triple harmonic generation and the quintuple harmonic generation after AC magnetization using nano superparamagnetic materials for experiment, and the precision obtained was greater than 1 degree in a range of 20° C. to 50° C. Temperature-related constants of the magnetic nanoparticles, such as size, saturation magnetic moment and so on can be precisely and repeatedly pre-measured outside vivo, and magnetic parameters can be predetermined. Uncertainty of concentration distribution and space distribution of magnetic nanoparticles in vivo is to cause very large error of temperature measurement in vivo. Uncertainty of pixel distribution in vivo causes temperature of nuclear magnetic resonance can only implement measurement of temperature difference.